EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: ironsniper1 on January 28, 2024, 10:29:25 pm
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hey all, while i am waiting for parts for my other vcr, i found one for free on facebook marketplace and while it works almost perfectly and has great picture there is one issue, it will not play tapes that need to be rewound, if the tape is at the start it plays fine, not sure what the issue is any advice would be great
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What do you mean exactly by "will not play"? Refusing to go into play mode? Plays for a few seconds and stops?
Do rewind and fast forward work?
The only thing that comes to mind is a slipping clutch or idler that's producing insufficient torque to rotate the takeup reel as it gets heavier near the end of the tape.
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What do you mean exactly by "will not play"? Refusing to go into play mode? Plays for a few seconds and stops?
Do rewind and fast forward work?
The only thing that comes to mind is a slipping clutch or idler that's producing insufficient torque to rotate the takeup reel as it gets heavier near the end of the tape.
wont play, rewind or fast forward if the tape needs to be rewound, here is a video of the issue https://imgur.com/xUt4I2L
i also attached a picture of two tapes exactly the same movie, the one on the left plays,rewinds and fast forwards without issue the one on the right wont do anything, i did take that tape on the right and rewound it by hand and after that it played fine
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for sure your 2x loading arms does'nt go all the way ... and generate a problem
belts, clutch to check
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only one belt and its, clutch dont know what or where that is, but if it was a belt issue then no tapes would play, but if i put in a tape that has been rewound it plays fine
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because the wheel weight is not the same when full and empty, for sure its a "drive" problem, could be a clutch wheel assembly
one thing you could do is empty a cassete just keep the contour frame, and sometimes you see a gear going from the supply wheel to the takup wheel
need to find the service manual and see the drive mecanism parts
hitachi had tons of theses problems, and you had to chane a mechanical assembly to get things working again
some clucth where easily repairable, you could dissasemble them, use a tooth brush on the felt disk, and slightly over-expand the spring to give it more push force
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so far i havent found a manual for this one
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The top-motored drum suggests this is a relatively recent model that likely doesn't have rubber idler drive. Could you post more pictures of the internals? That can help identify the chassis/mechanism as they often used the same mechanicals across many different models.
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here is a picture if there is anything you want zoomed in on just let me know where
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As I recall, Mitsi's suffered from IR LEDs going low emission causing all sorts of weird mecha-con issues...
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if it were that i feel like there would be more issues
when this issue happens I do get an error on the vcr E2
The "E2" error means "E2 - Loading motor lock in the unload direction"
It could be a worn/broken tooth on one of the loading mechanism gears or a foreign body causing it to jam.
I find it odd though it only does it with tapes that need to be rewound, from reading the error I would think it would do it with all of them
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only one belt and its, clutch dont know what or where that is, but if it was a belt issue then no tapes would play, but if i put in a tape that has been rewound it plays fine
In play mode, the take-up spool is driven by a belt (probably two) via a slipping clutch from the capstan flywheel. The slipping clutch (usually made of plastic discs and a felt pad) is needed because the speed of the take-up spool must vary according to diameter of the tape on the take-up spool while the capstan speed is constant.
The take-up spool takes more effort to turn as the diameter of wound tape increases. If the belt(s) are glazed or stretched, or the clutch becomes too worn, then there is no longer enough torque to turn the take-up spool and it stops. The VCR probably has a rotation sensor on the take-up spool to detect it stopping otherwise the VCR would fill up with a tangle of loose tape! It is sometimes possible to improve the clutch torque by taking it apart and using some very fine abrasive paper to slightly roughen the plastic disc surfaces, which will have become very polished over the years, but it is best to replace it - and it is more likely to be a belt. Irrc, they used to come as a kit anyway.
The take-up clutch and belt(s) are probably on the underside of the mechanism. This is a completely separate system from the one used for fast wind and rewind.
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only one belt and its, clutch dont know what or where that is, but if it was a belt issue then no tapes would play, but if i put in a tape that has been rewound it plays fine
In play mode, the take-up spool is driven by a belt (probably two) via a slipping clutch from the capstan flywheel. The slipping clutch (usually made of plastic discs and a felt pad) is needed because the speed of the take-up spool must vary according to diameter of the tape on the take-up spool while the capstan speed is constant.
The take-up spool takes more effort to turn as the diameter of wound tape increases. If the belt(s) are glazed or stretched, or the clutch becomes too worn, then there is no longer enough torque to turn the take-up spool and it stops. The VCR probably has a rotation sensor on the take-up spool to detect it stopping otherwise the VCR would fill up with a tangle of loose tape! It is sometimes possible to improve the clutch torque by taking it apart and using some very fine abrasive paper to slightly roughen the plastic disc surfaces, which will have become very polished over the years, but it is best to replace it - and it is more likely to be a belt. Irrc, they used to come as a kit anyway.
The take-up clutch and belt(s) are probably on the underside of the mechanism. This is a completely separate system from the one used for fast wind and rewind.
in the video i posted above it does that for play, rewind and fast forward
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The reported symptoms include not rewinding of the problem tape. In that mode the take up reel is not driven so the issue is not with belt or clutch that is exclusive to the take up spindle.
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The reported symptoms include not rewinding of the problem tape. In that mode the take up reel is not driven so the issue is not with belt or clutch that is exclusive to the take up spindle.
i did rewind the problem tape by hand (which took forever |O ) and i put it in and it played fine
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The reported symptoms include not rewinding of the problem tape. In that mode the take up reel is not driven so the issue is not with belt or clutch that is exclusive to the take up spindle.
i did rewind the problem tape by hand (which took forever |O ) and i put it in and it played fine
Please explain how your reply is relevant to what I wrote.
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Extra info
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Extra info
Not extra as you had already stated that in a previous post in which you wrote " i did take that tape on the right and rewound it by hand and after that it played fine"
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Well I cleaned all the sensors I could find and still no luck
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That's the "alpha deck" mechanism. You can find a manual for the HS-U449 online which uses the same chassis. Are you able to manually load and unload it fully (without a tape) by turning the loading motor? If there's binding or tightness, don't force it; disassemble and determine the reason it's not moving smoothly. It looks like this mechanism doesn't have a mechanical mode switch, but instead an optical one, so check that it's clean of dust and dirt.
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what does the loading motor look like? if its what i think it is and i could be wrong i dont think i can do that
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It’s the motor on the top right corner of the deck.
To load manually without cassette, you need to unlock those two little hooks on the cassette tray or lift (not sure about the correct English phrase), that prevent loading without properly inserted cassette.
I would not recommend to do manual loading with a cassette as the tape will be crumpled on ejection unless you turn the capstan motor as well
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I couldn’t get it to turn by hand and couldn’t get it to unlock, it works fine with a tape that’s rewound as I watched it but it doesn’t work well with tapes that are at the end
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Somehow you need to debug the mechanism…
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I forgot to add, I managed to get it to rewind a couple of tapes that were at the end by hold down the rewind button, I do not know why this worked but it did but I haven’t been able to do it again, could capacitors be the issue maybe? I mean I doubt it but I can’t think of anything else
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The theory is that the loading motor consumes too much current and the power supply breaks down?
Either you probe the supply voltage with a scope during loading or you cool down the power supply with cold spray.
So ESR of bad caps will rise and further increase instability and even rewound cassettes won’t work.
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like i said i cant think of anything else, everything looks fine, nothing is broken or missing teeth, the motor works perfectly the only thing i have to go by is that E2 error
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Remove the deck from the rest of the unit and cycle it manually by hand, after removing the loading motor, and check for binding or tightness.
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i did and i couldnt get it to move by hand it was like it was locked or something
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Found this button in the back that just says reset and after that I managed to load and rewind two tapes, after that nothing, won’t do it again, I wonder if it could be an ic issue or cap issue or something screwy like that
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i grabbed a copy of the service manual for the hs-u449 which i think has the same innards as mine and noticed mention of a E2PROM which when i google it says its an eeprom, could this hold settings or something and possibly be on its way to dying?
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No
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i just noticed that if i carefully push a tape in it wont play, if i push it in hard then it will play
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i just noticed that if i carefully push a tape in it wont play, if i push it in hard then it will play
already tougt of tat and it didnt make a difference
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Like I said, remove the mechanism and make sure it is not binding throughout the whole range of travel of the loading cycle. Then clean the mode switch --- optical encoders in this unit, so check that they're free of dust and dirt.
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Sounds less of a player issue but more a tape issue. Those tape don't last forever and it's possible that the lock inside the tape case is worn and won't unlock completely when inserted into the machine. Aggressively inserting into the machine would likely cause it to unlock as it should.
Also check the pin that unlocks the tape that it's not bent or worn down or the frame that it sits on isn't bent.
Another issue is if the tape isn't wound evenly on the reel. That can also cause the reels to bind or drag down enough to stop the player.
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i cant see it being a tape issue since if the tape is at the very beginning it will load perfectly every time but if its at the very end it doesnt